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Developing Novel Multiobjective Approaches for Direct Angle and Aperture Optimization Problem in Intensity Modulated Radiation Therapy

Fallahi, Ali | 2023

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 56030 (01)
  4. University: Sharif University of Technology
  5. Department: Industrial Engineering
  6. Advisor(s): Akhavan Niaki, Taghi; Mahnam, Mehdi
  7. Abstract:
  8. Intensity-modulated radiation therapy is a well-known technique to treat cancer patients worldwide. A treatment plan in this technique requires decision-making for three main problems: selection of beam angles, intensity map calculation, and leaf sequencing. Previous works have investigated these problems sequentially. In this research, we present a new integrated framework for simultaneous decision-making of directions, intensities, and apertures shape, called direct angle and aperture optimization, and develop a mixed-integer nonlinear mathematical model for the problem. At first, the problem's single-objective model is established using the quadratic dose penalty function. After that, regarding the challenges of the single-objective version, such as the organ's weights modification, a multiobjective version of direct angle and aperture optimization is presented in which each patient organ can be considered as an objective. Due to the problem's nonlinearity and dimension, metaheuristic algorithms are utilized as the solution approaches. For the single-objective problem, three efficient metaheuristics based on differential evolution (DE) called classic differential evolution (cDE), discrete differential evolution (dDE), and adaptive hybrid discrete differential evolution-particle swarm optimization (ahdDE-PSO) algorithms are designed to solve the problem. Considering the possibility of existing more than three objective functions, a new generation of multiobjective metaheuristics, known as many objective metaheuristics, are presented as the solution approaches for the multiobjective problem. To this end, the many objective particle swarm optimization (MaOPSO), non-dominated sorting differential evolution based on reference points (NSDE-R), and non-dominated sorting genetic algorithm III (NSGA-III) algorithms are designed to solve the multiobjective direct angle and aperture optimization problem. Parameters calibration is performed using the Taguchi design of experiments. The performance of the algorithms is evaluated by solving the problem for ten real cases of liver cancer disease from the TROTS data set. The results are comprehensively analyzed using several computational and clinical measures
  9. Keywords:
  10. Intersity Modulated Radiation Therapy ; Nonlinear Programming ; Meta Heuristic Algorithm ; Multiobjective Optimization ; Direct Angle and Aperture Optimization ; Many Objective Metaheuristic Algorithms ; Cancer Treatment

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